Table 5:
Assessing the risk of bias in each review using the AMSTAR-2 criteria
| AMSTAR-2 criteria | Hadders-Algra et al.18 | Morgan et al.16 | Morgan et al.17 |
|---|---|---|---|
| 1. Did the research questions and inclusion criteria include the components of PICO? | + | + | + |
| 2. Did the review contain an explicit statement that the methods were decided before the review, justifying any significant deviations? | +/− | +/− | +/− |
| 3. Did the review authors explain their selection of the study designs for inclusion in the review? | + | − | − |
| 4. Did the review authors use a comprehensive literature search strategy? | +/− | +/− | +/− |
| 5. Did the review authors perform study selection in duplicate? | + | + | + |
| 6. Did the review authors perform data extraction in duplicate? | + | + | + |
| 7. Did the review authors provide a list of excluded studies and reasons why they were excluded? | + | + | − |
| 8. Did the review authors describe the included studies in adequate detail? | + | + | + |
| 9a. Did the review authors use an adequate technique to assess the risk of bias in individual studies included in the review (RCTs)? | + | + | − |
| 9b. Did the review authors use an adequate technique to assess the risk of bias in individual studies included in the review (NRSI)? | NA | NA | − |
| 10. Did the review authors report on the sources of funding for the studies included in the review? | − | − | − |
| 11a. If a meta-analysis was performed, did the review authors use appropriate methods for statistical combination of results (RCTs)? | NA | + | NA |
| 11b. If a meta-analysis was performed, did the review authors use appropriate methods for statistical combination of results (NRSI)? | NA | NA | NA |
| 12. If a meta-analysis was performed, did the review authors assess the potential impact of risk of bias in individual studies included on the results of the meta-analysis or other evidence synthesis? | NA | + | NA |
| 13. Did the review authors account for risk of bias in individual studies when discussing/interpreting the results of the review? | + | + | + |
| 14. Did the review authors provide a satisfactory explanation, and discussion of, any heterogeneity observed in the results of the review? | + | + | + |
| 15. If they performed quantitative synthesis, did the review authors carry out an adequate investigation of publication bias (small study bias) and discuss its likely impact on the results of the review? | NA | + | NA |
| 16. Did the review authors report any potential sources of conflict of interest, including any funding they received for conducting the review? | + | + | + |
PICO, participants, interventions, comparators, and outcomes; RCT, randomized controlled trial; NRSI, non-randomized studies of interventions; NA, not applicable.